Surge-reliever or safety device for tow-lines.



W. A. DUNGANSON.

SURGE EELIEVER 0R SAFETY DEVICE FOR TOW LINES.

APPLICATION FILED JAN.22,1909.

957,315. Patented May 10,1910.

@u 75 77 0o 25 Z L@ )n/Z7 [7 /74/ f=/ /gli [s Y/ll//lwl//il//IY F E k Izf@ WILLIAMALONZO DUNCANSON, OF BOSTON, MASSACHUSETTS.

SURGE-RELIEVER Gl?, SAFETY DEVICE FOR TC'/V-LINES.

Specification of Letters Patent.

Patented May 10, 1910.

Application iiled January 22, 1969. Serial No. 473,752,

To oil whom it may concern:

Ee it known that I, lViLLnur A. DUNCAN son, of Boston, in the county ofSuffolk and State oit Massachusetts, have invented certain new anduseful Improvements in Surge-Relievers or Safety Devices for Tow- Lines,ot which the following is a specification.

rl`his invention relates to an elastic device adapted to be interposedbetween two in elastic sections of a tow line, which coorects a tug' ortowing vessel with a barge or other vessel being towed, the said elasticdevice having provisions for relieving the sudden shock exerted upon itby independent movements of the two vessels due to ware action, andpreventing or reducing` to the minimum the liability of breakage of thetow line duc to such shocks.

T he invention has for its object to pro vide a safety device or surgereliever oit improved construction which includes a spring adapted to becompressed by an inr'reas in the strain on the tow line, and thusprei-rent a sudden and an injurious increase ot strain upon the line,the construction being` such that the device is adapted, when the limitot compressibilitv of the spring has been reached, to withstand themaximum strain exerted on the tow line.

The invention consists in the improve ments which T wiil now proceed todescribe and claim.

Of the acocmpanying drawings, AForming a part of thisspeciicaticm-Figure 1 represents a longitudinal section of a safetydevice embodyingl my invention, the device being shown in the adjustmentwhich it normally assumes when no strain is exerted on the tow line.Fig. 2 represents a similar view, showing the device in the aojustmentwhich it assumes when the maximum strain is exerted on the tow line.

The same reference characters indicate the same parts in both figures.

In the drawings, 12 and 13 represent two sections of a tow line betweenwhich my improved safety device is interposed. Said safety devicecomprises an outer tubular member 111 having an internal head orabutment 15, and an inner tubular member 1G, which is slidable endwisein the member 14, and has a head 17 opposed to the fixed head 15 of theouter member. lilith the head 17 of the inner member is engaged a rod 18which has a sliding tit in an oriiice formed in the center of the head15 of the outer member. 19 represents a spring which surrounds the rod1S, and bears upon the heads 15 and 17, the normal expansion ot' thespring separating the heads 15 and 17, as indicated in Fig. 1.

2O represents a boltwhich passes through longitudinal slots 21 in theinner member 1G, and orifices 22 in the outer member 14, said oriiicesand slots being arranged to coincide, said bolt being connected by aclevis Q3 with the tow line section 18.

Q4 represents a bolt which is slidable in slots 25 formed in the outertubular member 14, said bolt passing through a socket formed for itsreception in the outer end ot the rod 1S, and having a clevis Q6 whichconnected with the tow line section 1Q.

lVhen the tow line is not under strain, and the spring 19 is expanded,the inner ends oi slots 21 bear against bolt 20, and the bolt Qf-Ltbears against the inner ends ot the slots Q5, as shown in Fig. 1. ldlhena strain is exerted on the tow line sutiicicnt to compress the spring19, the heads 15 and 1T are moved toward each other, thus causing Ithecom pression of the spring 19, and at the same time, the member 16 ismoved to bring the outer ends of the slots 21 toward bolt Q0, and thebolt 2li-is moved toward the outer ends of the slots 25.

The described movement of the parts is resisted and made gradual by thespring 19. TWhen the limit ot the compressibility of the spring isreached, the outer ends of the slots 21 are against bolt Q0, and thebolt 2i comes at the same time to bearing on the outer ends of the slots25, as indicated in Fig. :2. The strain on the tow line is therefore.supported at six points, vizz, the outer ends of the two slots 21, theouter ends of the two slots 25, and the outer sides of the two orificesQ2, a plurality oit abutments for the bolts 2O and Qi being thusprovided when the spring is fully compressed. This division of thesupport of the maximum strain exerted on the tow line prevents liabilityot the breakage of the safety device, the strength ot' the latter beingadequate to any strain that can be sustained by the tow line sections 12and 13.

The clevises Q3 and 2G distribute the strain on the bolts Q0 and 24:,and maintain said bolts substantially at right angles with thelongitudinal axis of the tubular members, so that there is no liabilityof the bolts becoming inclined relatively to said axis, and sticking orbinding in the slots in which they are movable.

It will be seen that the heads 15 and 17 and the portion of the outertubular member 14 intervening between said heads, constitute a chamberwhich contains the spring 19, said chamber being adjustable in length bythe movement of the heads relatively to each other. The portion of theouter tubular member 14 constituting the wall of said chamber ispreferably provided with orifices 27 which permit the entrance 4of waterinto the said chamber when the heads are moving from each other, and theexit of water therein when the heads are moving toward each other. lVhenthe advice is in the adjustment shown in Fig. 1, the heads 15 and 17being at their maximum separation, the chamber formed by said heads andthe intervening portion of the tubular member 14, is filled with water,assuming that the device is at such a portion of the tow line that itwill be submerged when in use. It will be seen, therefore, that when thesaid chamber is contracted by the movement of the heads 15 and 17 towardeach other, the 'water will be expelled through the orifices 27, itsexpulsion being gradual and retarding the inward movement of the heads,means being therefore provided for aiding the spring 19 in causing agradual absorption of violent shocks exerted on the tow line.

It will be seen that the described construction provides a telescopicdevice, the inner and outer members 14 and 16 of which are normallyextended by a spring, bolt 20 being slidable with the outer memberrelatively to the inner member, and bolt 24 slidable with the innermember relatively to the outer member, said bolts being provided withmeans, as the clevises 23 and 26, for engaging two tow line sections,and a plurality of abutments (formed by portions of the slots 21, 25,and of the orifices 22) which collectively bear the strain on the towline when the spring is compressed to a predetermined extent, the saidabutments preventing further and injurious compression of the spring.

The invention is not limited to the means for retarding the compressionof the spring by liquid introduced between the heads 15 and 17, althoughI regard this as a desirable feature. The heads 15 and 17 may, however,be constructed to serve simply as supports for the rod 18, and asabutments for the spring instead of being of water tight construction,in which case the orifices 27 may be omitted. Said orices are preferablygraduated in size, as shown, the arrangement being such that as theliquid chamber is contracted, the larger orifices are successivelyclosed by the inner member 16.

I claim:

1. A safety device of the character stated, comprising an outer tubularmember having a fixed internal head and longitudinal slots adjacent oneend, an inner tubular member slidable lengthwise in the outer member andhaving a head at one end portion, and slots adjacent the other end, arod engaging with said head and having a. sliding it in the head of theouter member, a bolt engaged with said rod and movable in slots of theouter member, a bolt carried by the outer member and movable in slots inthe inner member, said bolts having means for engagement 'with tow linesections, and a spring interposed between the said heads and adapted tobe compressed by an increase of strain on the tow line, the said slotsand orifices providing a plurality of abutments for said bolts whichlimit the compressibility of the spring.

2. A safety device of the character stated, comprising inner and outertelescopic members provided with opposed internal heads forming the endsof an adjustable liquid chamber, the outer member having orificescommunicating with said chamber, a spring which normally extends saidmembers, and bolts slidable with each member relatively to the othermember, and provided with means for engaging tow line sections, theliquid contained in said chamber retarding the compression of the springwhen strain is exerted o-n the tow line.

In testimony whereof I have affixed my signature, in presence of twowitnesses.

WILLIAM ALONZO DUNCANSON. ldfitnesses C. F. BROWN, P. IV. PEZZETI.

